X68C75PI datasheet(13/26 Pages) XICOR

13 / 26 page

X68C75 SLIC® E2

X68C75 location E024H. The XSLIC software, a PC

based communication driver, automates changing of

the default parameters when using its SETUP option

menu. The boot-firmware (SLIC) residing on the X68C75

contains a lookup table which can be accessed from the

subroutine (EXEC_FUNC), located at location E120H.

Two bytes are used per table entry. The EXEC_FUNC

input requirements are as follows:

B = Contains a function number from the following

function table.

The table entry at location (E14E-E14FH) is reserved for

user’s application code. This function will be executed

on power-up if the SLIC receives any characters other

than those for the RESET (ASCII ‘R’), or ID (ASCII ‘X’)

commands. This table entry can be changed to point to

other code responsible for power-up initialization. This

method is preferred to changing the reset vector, since

the SLIC code can still be invoked upon power-up.

Other functions available through the EXEC_FUNC

calls are as follows:

the interrupt is enabled, an external interrupt will be

asserted at the completion of the internal write cycle.

The interrupt is cleared by setting EOW to “0”.

USING A PORT IN BIDIRECTIONAL MODE

In order to use a port in bidirectional mode, it has to be

configured as an open drain output port. Small pull-up

resistors are required on all port output pins. Bit positions

in the port data register corresponding to port inputs

should contain “1”. The inputs are then read by access-

ing PPR. Data is not latched into the device, so the inputs

must stay valid throughout the read cycle. The port

strobe pin is configured as an output and cannot be used

as port latch clock input.

SLIC FUNCTIONS (68HC11 Specific SLIC)

The resident SLIC E2 has designated memory spaces

allocated for its use. The user’s application code should

avoid using these areas as part of its code segment,

otherwise it will overwrite the SLIC E2. Version 3.0 of the

X68C75 SLIC E2 occupies 192 bytes in the upper

memory bank, FF00-FFC0H, and 336 bytes in the lower

bank’s address range E000-E14FH. Prior to download-

ing code, assemble and link the source files using the

above address information. Use memory space taken

up by the SLIC E2 as a run-time data storage, if there is

no further need to modify the X68C75 SLIC E2 content.

The current version of the SLIC E2 configures the 68HC11

serial port to the variable baud rate mode. It sets a timer

prescalar value for a system clock rate of 8MHz. For

other clock rates, the end user must recalculate timer 1

reload value for 9600 baud rate and write it into the

Figure 13.

SLIC

E000

E150

FF00

FFC0

SLIC

User’s Program/Data

2899 ILL F15

ISR & Reset Vectors

FFFF

FUNCTION NO.

DESCRIPTION

0 - PROC_PROG

Download and program a

page

1 - PROC_BPR

Program BPR

2 - RESET

Start execution from

location E000H

3 - PROC_VER

Download and verify a page

4 - DUMMY

Command not recognized

5 - INIT_UART

Initialize UART parameters

to default

6 - PROG_PG

Program a page

7 - SEND_CHAR

Send a character to the

UART

8 - GET_CHAR

Read a character from the

RAM receive buffer (40H-5FH)

9 - SDP_HI_PLANE

Generate SDP off sequence

for upper plane

10- SDP_LO_PLANE Generate SDP off sequence

for lower plane

11- USER_CODE

Execute user’s code

2899 PGM T03.2

Table 2.

For detailed information about the listed functions, in-

cluding their input requirements, refer to the SLIC soft-

ware specification document.

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